In the world of
hipsters and wannabes, wedding blogs and Pinterest, anyone who is between the
ages of 20 and 40, or knows anyone between the ages of 20 and 40, will have
already been familiar with the adorable image of a tandem bicycle on a wedding invitation
(if you haven’t yet, don’t worry – it’s coming.) However apt the image of a tandem bicycle
might be for a new marriage or young love, in the unexpected setting of
Parkinson’s disease, it makes an even more fitting, touching and literal symbol of not only love and
devotion but even cutting edge medical promise, as well.

~ ~ ~

Parkinson’s
Disease is a devastating neurological condition in which the afflicted slowly
lose control over the movements of their body.
Slowness, tremors, deterioration of speaking ability and balance are
some of the major manifestations of this disorder that affects an estimated 1
million Americans, and for which there is no cure. In addition to problems with movement, people
with PD also commonly suffer from depression, dementia, sexual difficulties and
sleep disturbances.

PD is a
progressive, degenerative nerve disorder that affects the neurons in the brain
that control movement. The main neurons affected are located in the substantia
nigra of the basal ganglia, which serve as the coordination center for signals
coming from the cortex of the brain to the spinal cord in order to move muscles
on command. Their deterioration causes a
deficiency of dopamine, a key chemical for proper brain function and the main
neurotransmitter that they produce. This
is where the bicycles come in.

In the spring of
2010, Dr. Bastiaan Bloem of the Radboud University Nijmegen Medical Center in
the Netherlands was visited by a patient with advanced Parkinson’s. This man had been afflicted with the
condition for ten years, and he had been left nearly unable to walk at all,
with a severe balance deficit, feet that repeatedly froze on the floor and a
tremor that would cause him to fall after just a few shuffling steps.

This patient told
his doctor that he could, however, still ride his bike perfectly – and was
determined to prove it. So doctor and
patient went out to the parking lot, and with the help of a nurse to get him on
the bike and shoved off, the patient rode off in perfect control, making a
U-turn at the end of the parking lot and pedaling smoothly back, all
Parkinson’s symptoms vanished. The
moment he brought the bike to a halt and stepped off, he froze immediately,
unable to move his legs in a single step.
The episode was filmed and photographed, and the images were published
in the April 1st, 2010 issue of the New England Journal of Medicine.

Dr. Bloem –
wheels turning, as it were – then asked 20 of his other patients severely
affected by Parkinson’s disease if they could ride a bike. It turned out that they all could.

One explanation
for the finding, according to Dr. Bloem, could be that bicycling uses a
different part of the brain than walking – and that this part might not be so
severely affected by Parkinson’s disease. It could be, perhaps, that bicycling doesn’t
require very much input from the part of the brain that’s diseased in
Parkinson’s patients, the basal ganglia.
It’s the basal ganglia that processes signals for voluntary movements,
and its impairment is the reason Parkinson’s patients freeze – the part of the
brain that tells them what to do next isn’t functioning. It’s certainly
possible that one of the reasons the Dutch patient wasn’t showing any sign of
Parkinson’s while riding a bike is that riding a bike doesn’t require a lot of
signal processing in the basal ganglia. Nurses helped the patient onto
the bike and got him going, but once he was going, he could keep doing the same
thing without much thought about motor strategies. (Gives new significance to the old adage,
“like riding a bike.”)

Another theory
regarding the reason for this phenomenon is that it could be that the rhythmic
pressure of the pedals on patients’ feet cues the nervous system to allow a
cycling movement. He suggests that
the rotary motion of the pedals may provide an external pacing cue that keeps
the Parkinson’s patients on track. Given appropriate visual or emotional
cues, people with Parkinson’s can dance, walk without freezing and perform
complex movements for a few minutes at a time.
For example, there are many stories about patients with PD being caught
in a building on fire and finding themselves able to run down stairs and escape
safely, only to have symptoms return as soon as they got outside. But this kinesia paradox, as it is known,
does not last long, and is entirely different from being able to ride a bike
flawlessly for miles at a time. Until now, it was not known that
patients with Parkinson’s could ride bikes.

In
fact, the "bicycle sign" might help
clinicians differentiate between the Parkinson’s disease and Parkinsonism of
other disorders. Patients with atypical
Parkinsonism lose their ability to cycle during the early phase of the illness,
while patients with Parkinson's disease continue to ride well. This has important treatment implications
because atypical Parkinsonism disorders can often look very similar to
Parkinson's disease, but respond differently to therapy. There is a legitimate question of whether or
not the bicycle sign is universally applicable, given environmental and
cultural differences between patients (Dr. Bloem and his patients
reside in the the Netherlands, where absolutely everyone rides a bike.)

~ ~ ~

While
there are a number of useful medications that help ease Parkinson’s disease
symptoms for a few hours, advancements in significant relief have eluded
Parkinson’s researchers. In a surprising
and somewhat whimsical discovery, new evidence suggests that tandem cycling may
bring a longer relief from the disease’s symptoms, with improvements lasting
for weeks at a time.

The
serendipitous discovery was made in 2003 when neuroscientist Jay Alberts, then a Parkinson’s
disease researcher at Emory University in Atlanta, rode a tandem bike across
the state of Iowa with his friend Cathy Frazier, a Parkinson’s patient. The two were riding the staewide bicycle tour
to raise awareness of the neurodegenerative disease, but they also found,
much to both of their surprise, that her tremors disappeared after about an
hour of riding. She told him that she
felt great while riding and that it was as if she didn’t have the disease. They also noticed that her handwriting
improved. Patients with Parkinson’s often
develop micrographia, meaning that their handwriting becomes small and
illegible. Alberts’ friend Cathy had
noticed the progressive shrinking and illegibility of her handwriting as her PD
progressed, but during this bike tour, she wrote on a birthday card with
beautiful, large, legible letters. It
made Alberts take note.

Alberts
wondered if this mysterious side effect of the tandem bike ride held an
intriguing medical possibility: the improved motor control in the arms and
hands even though only the legs were exercising seemed to suggest that there
was some change taking place in the central nervous system that improved global
motor function, perhaps by triggering the release of biochemical messengers.

Now a
researcher at the Cleveland Clinic, Jay Alberts has conducted several studies with
Parkinson’s patients inspired by these discoveries and his passion for biking. Many patients are able to lower their
medication dosages and regain motion in extremities. Other patients have regained their sense of
smell from bike riding, which is commonly lost in PD and often one of the first
symptoms that patients notice before being diagnosed.

Dr. Alberts had
volunteers with Parkinson’s ride a solo stationary bicycle at his or her own
pace. Most chose a pedaling cadence of
around 60 revolutions per minute, a relatively non-strenuous level of exertion. He then placed them on the back seat of a
tandem bike that had been modified to ensure that the back rider would have to
actively pedal; he or she could not just passively let the pedals turn. On the tandem, the rider in front had been
instructed to pedal at a cadence of about 90 RPM and with higher force output
or wattage than the patients had produced on their own. The result was that the riders in back had to
pedal harder and faster than was comfortable for them.

Tandem bike riding has turned out to be beneficial therapy
for patients, but Alberts determined it was because the exercise was
forced. The challenge of pedaling much
faster than normal activates the part of the brain that controls body movements
and releases dopamine, which is what improves symptoms in Parkinson's patients.
According to Alberts, the
medications often given for symptom improvement in PD activate certain areas of
the brain or increase the blood flow there, and an almost identical pattern of
activation is seen in the brains of patients who have done forced exercise.

This is an exciting finding
because it contrasts with some earlier results involving voluntary exercise and
Parkinson’s patients. In those
experiments, the activity was helpful, but often in a limited, localized way. Weight training, for instance, led to stronger
muscles, and slow walking increased walking speed and endurance. But such regimens typically did not improve
Parkinson’s patients’ overall motor control.

The forced pedaling regimen, on
the other hand, did lead to better full-body movement control, which prompted
Dr. Alberts to conclude that the exercise must be affecting the riders’ brains
as well as their muscles. His theory
that was substantiated when he used functional M.R.I. machines to see inside his
volunteers’ skulls. The scans showed
that, compared with Parkinson’s patients who hadn’t ridden, the tandem
cyclists’ brains were more active.

Dr. Alberts suspects that in
Parkinson’s patients, the answer may be simple mathematics. More pedal strokes per
minute cause more muscle contractions than fewer pedal strokes, which, in
consequence, generate more nervous-system messages to the brain. There, he
thinks, biochemical reactions occur in response to the messages, and the more
messages, the greater the response.

This
raises fascinating questions not only about whether exercise can help to combat
the disease but also whether intense, essentially forced workouts affect brains
differently than gentler activity does, even in those of us who are healthy. In lab animals, forced and voluntary exercise can lead to
different outcomes. Mice and rats generally
enjoy running, and they will voluntarily hop aboard and run on a wheel placed
in their cages. But if an animal is
placed on a treadmill and the speed controlled so that it must keep pace, often
with help from a finger prod or electrical shock, the activity becomes forced.

Interestingly, the effects in
animals, especially on their brains, are typically more beneficial after forced
exercise. Inone study from 2008, rats forced to
run wound up with significantly more new brain cells after eight weeks than
those who ran when they chose, even though the latter animals ran faster. And inanother
experiment, mice that were required to exercise on treadmills subsequently
performed better on cognitive tests than those given access to running wheels.

A small
eight-week study was launched to gauge the effects of forced exercise in which the
patients underwent hour-long sessions of forced riding, pedaling at 80-90 RPM. And the results were impressive: there was a
35% improvement in motor functioning, significant lessening of tremors and better body control for the
patients who did the forced exercise compared with those exercisers who pedaled
a stationary bike at their own pace, and the improvement lasted for four weeks
after the cycling sessions ended.

Whether forced exercise would
similarly affect healthy brains is unknown at this point, he says, as is the
question of whether riding on the back of a tandem behind a stronger cyclist is
the only qualifying exercise. It seems
likely that intense exercise of any kind should produce comparable brain
reactions. There is even some data
showing that people who exercise intensely have a lower risk of developing
Parkinson’s and other neurological diseases.

In
addition to motor difficulties, individuals with Parkinson's disease often
experience cognitive declines. And although
pharmacologic therapies are helpful in treating motor deficits in PD, they do
not appear to be effective for cognitive complications. While acute bouts of moderate aerobic exercise
have been shown to improve cognitive function in healthy adults, individuals
with PD often have difficulty with exercise, for obvious reasons. Another recent study looked the effects of
passive leg cycling on executive function in PD, which was assessed with two
different tests before and after the cycling. Volunteers showed significant improvements on
the test after exercising, and the difference between times to complete the two
exams significantly decreased from pre- and post-cycling times. It is thought that the improved executive
function after passive cycling may be the result of increases in cerebral blood
flow, which correlates with theories regarding post-cycling motor function
improvement as well, suggesting multiple benefits from forced exercise in
patients with PD.

Regardless,
bicycling offers patients an opportunity to be symptom-free while they are
riding, to look and feel normal, and to get some real cardiovascular exercise
even when their disease is so far advanced that they cannot walk. The humble tandem bike was one
of the Top 10 Medical Innovations for 2010 at Cleveland Clinic. Remember how awesome that is the next time a
bride-to-be tells you how totally adorable she thinks it would be to exit her
reception on one. It could add just the
perfect element of kitsch to her perfectly color-coordinated DIY wedding. But it could also hold the key to someday
saving lives.